How to add edge outlining to transparent objects in bge
You need 2 object, one with a wire transparent material the other with solid material.



You can adjust the alpha in Transparency.



3 And can control with a script, also control the scale.
script.py (example)
from bge import logic

class ObjectsList():
    def __init__(self, controller):
        self.obj = [obj for obj in logic.getCurrentScene().objectsInactive if not obj.name[-1].isdigit()]
        self.objLiner = [obj for obj in logic.getCurrentScene().objectsInactive if obj.name[-1].isdigit()]

    def main(self):
        print(self.obj)
        if len(self.obj) &gt; 0:
            obj = self.obj.pop(0)
            outliner = self.objLiner.pop(0)
            ##creating a solid obj
            mainObj = logic.getCurrentScene().addObject(obj.name)
            ##creating outliner
            outlinerObj = logic.getCurrentScene().addObject(outliner.name)
            ##scaling up
            outlinerObj.localScale = [1.04]*3
            ##changing alpha
            outlinerObj.meshes[0].materials[0].alpha = 0.3
            outlinerObj.suspendDynamics(True)
            outlinerObj.setParent(mainObj)
            print('obj created...')

def main(controller ):
    if not 'init' in controller.owner.getPropertyNames():
        controller.owner['objHandler'] = ObjectsList(controller)
        controller.owner['init'] = True
        return
    controller.owner['objHandler'].main()


Related
Python API (bge object material)
bge.types.KX_BlenderMaterial.alpha
I couldnt found relate documentation about change material type: wire